The design lowest navigable water level is a primary index to the channel grade division.But differ- ent method can get different calculated result,and that even brings contradiction to decide the navigation grade.In ...The design lowest navigable water level is a primary index to the channel grade division.But differ- ent method can get different calculated result,and that even brings contradiction to decide the navigation grade.In this paper the differences between guaranteed rate method and guaranteed rate-frequency method on the fundamental concept of guaranteed rate and the calculated result are carried out.According to the theoreti- cal expression forms of the two methods,the reason leading to the difference is an...展开更多
【目的】三峡库区消落带受周期性的水位涨落及冬季长时间深水淹没影响,碳汇能力遭受严重破坏。如何恢复并充分发挥消落带生态系统的碳汇潜力,成为三峡库区生态治理的关键议题。【方法】针对复杂水位变化挑战,提出以林塘模式修复消落带...【目的】三峡库区消落带受周期性的水位涨落及冬季长时间深水淹没影响,碳汇能力遭受严重破坏。如何恢复并充分发挥消落带生态系统的碳汇潜力,成为三峡库区生态治理的关键议题。【方法】针对复杂水位变化挑战,提出以林塘模式修复消落带生态系统并提升碳汇能力的技术框架,选取位于三峡库区腹心的大浪坝消落带开展实证研究。运用CASA模型测算修复前后大浪坝消落带的净初级生产力(net primary productivity,NPP),基于植被生物量数据计算修复后大浪坝消落带与未修复对照组内不同高程带的碳汇能力,评估林塘碳汇系统的可持续效益。【结果】修复后大浪坝消落带的碳汇能力随时间推移明显提升,NPP由2012年的154.4 g C·m^(2)·a^(-1)增长至2016年的182.5 g C·m^(2)·a^(-1);各高程带的碳汇能力均显著高于对照组,并呈现出随海拔降低而减弱的趋势,170~175 m高程带碳汇能力达到1.827 kg C/m^(2),160~165 m高程带碳汇能力仅为0.830 kg C/m^(2)。林塘系统增强了生态系统的适应性和复原力,形成了适应水位变化的立体固碳模式并有效提升了碳汇效率。【结论】林塘碳汇系统是应对三峡库区复杂水位变化和长时间深水淹没挑战的适应性探索,显示出景观优化、生物多样性、经济效益与碳汇协同耦合的关键特征。研究成果能够为中国大型工程型水库消落带的治理及碳增汇提供科学依据与可复制推广的创新技术模式。展开更多
基金Supported by the National Key Basic Resarch and Development Plan (Grant 2003CB415200)
文摘The design lowest navigable water level is a primary index to the channel grade division.But differ- ent method can get different calculated result,and that even brings contradiction to decide the navigation grade.In this paper the differences between guaranteed rate method and guaranteed rate-frequency method on the fundamental concept of guaranteed rate and the calculated result are carried out.According to the theoreti- cal expression forms of the two methods,the reason leading to the difference is an...
文摘【目的】三峡库区消落带受周期性的水位涨落及冬季长时间深水淹没影响,碳汇能力遭受严重破坏。如何恢复并充分发挥消落带生态系统的碳汇潜力,成为三峡库区生态治理的关键议题。【方法】针对复杂水位变化挑战,提出以林塘模式修复消落带生态系统并提升碳汇能力的技术框架,选取位于三峡库区腹心的大浪坝消落带开展实证研究。运用CASA模型测算修复前后大浪坝消落带的净初级生产力(net primary productivity,NPP),基于植被生物量数据计算修复后大浪坝消落带与未修复对照组内不同高程带的碳汇能力,评估林塘碳汇系统的可持续效益。【结果】修复后大浪坝消落带的碳汇能力随时间推移明显提升,NPP由2012年的154.4 g C·m^(2)·a^(-1)增长至2016年的182.5 g C·m^(2)·a^(-1);各高程带的碳汇能力均显著高于对照组,并呈现出随海拔降低而减弱的趋势,170~175 m高程带碳汇能力达到1.827 kg C/m^(2),160~165 m高程带碳汇能力仅为0.830 kg C/m^(2)。林塘系统增强了生态系统的适应性和复原力,形成了适应水位变化的立体固碳模式并有效提升了碳汇效率。【结论】林塘碳汇系统是应对三峡库区复杂水位变化和长时间深水淹没挑战的适应性探索,显示出景观优化、生物多样性、经济效益与碳汇协同耦合的关键特征。研究成果能够为中国大型工程型水库消落带的治理及碳增汇提供科学依据与可复制推广的创新技术模式。
